1. Field of the Invention
The present invention refers to a method for controlling a manipulator, in particular a robot, of the type wherein a reference path is stored and reference increments are determined while following the path, and to a control device for a manipulator for performing such method.
2. Description of the Prior Art
In many applications a reference path of a manipulator is stored a priori offline, for example by teaching of positions which are to be reached successively by a manipulator-fixed reference coordinate system like the tool centre point (“TCP”). While executing a respective work program, an interpolating device then determines online reference increments for the single joints of the manipulator based on a stored path planned from said stored positions. The manipulator control aims to realize said reference increments in time increments determined by the path planning.
This is not always possible since for example joint drives cannot apply the necessary forces and torques. Thus, in present practice usually the path velocity is reduced by hand until torque limits and other limitations can be met. This so-called override method is mentioned for example in DE 199 59 330 A1.